UNI-T UT302+ UT303+ Series Infrared
Thermometers User Manual
Preface
Thank you for purchasing the new infrared thermometer. In order to use this product safely and correctly, please read this manual thoroughly, especially the Safety instructions part.
After reading this manual, it is recommended to keep the manual at an easily accessible place, preferably close to the device, for future reference.
Limited Warranty and Liability
Uni-Trend guarantees that the product is free from any defect in material and workmanship within one year from the purchase date. This warranty does not apply to damages caused by accident, negligence, misuse, modification, contamination and improper handling. The dealer shall not be entitled to give any other warranty on behalf of Uni-Trend. If you need warranty service within the warranty period, please contact your seller directly.
Uni-Trend will not be responsible for any special, indirect, incidental or subsequent damage or loss caused by using this device. As some countries or regions do not allow limitations on implied warranties and incidental or subsequent damages, the above limitation of liability may not apply to you.
Introduction
UT301A+/UT302A+/UT303A+ infrared thermometer (hereinafter referred to as the thermometer) can quickly and accurately determine the surface temperature by measuring the infrared energy radiated from the target surface. Itis suitable for non contact surface temperature measurement.
The D:S ratios are:
UT301A+: 12:1
UT302A+: 20:1
UT303A+: 30:1
Safety Instructions
⚠️Warning:
To prevent eye damage or personal Injury, please read the following safety Instructions before using the thermometer:
- Please do not irradiate people or animals with laser directly or indirectly.
- Please do not look at the laser directly or through other optical tools (telescope, microscope, etc.).
LASER RADIATION DO NOT STARE INTO BEAM 
OUTPUT <imW COMPLIES WITH EN60825-1:2014
⚠️Precautions:
- Do not look directly at the laser emitter.
- Do not disassemble or modify the thermometer or laser.
- To ensure the safety and accuracy of the thermometer, it should only be repaired by a qualified professional using the original replacement parts.
- If the battery symbol on the LCD display is flashing, please replace the battery immediately to prevent inaccurate measurement.
- Inspect the case before using the thermometer. Do not use the thermometer if it appears damaged. Look for cracks or missing plastic.
- Please refer to the emissivity information for the actual temperature. Highly reflective objects or transparent materials can cause the measured temperature value to be lower than the actual temperature.
- When measuring high temperature surfaces, please be aware not to touch them.
- Do not use the thermometer in an environment close to flammable or explosive materials.
- Using the thermometer around steam, dust, or environments with large temperature fluctuations may lead to inaccurate temperature measurement.
- To ensure measurement accuracy, please place the thermometer in the measurement environment for 30 External Structure
minutes before using.
@ Avoid keeping the thermometer near high temperature environment for long periods.
2 | Infrared sensor
Technical Specifications 3_| Trigger
4 | Battery cover
Model UT301A+ UT302A+ UT303A+ 5 | Tripod screw hole
D:S ratio 12:1 20:1 30:1 6 | LCD display
32°C~420°C/ 32°C~700°C/ 32°C~800°C/ 7 | MODE button
Measuring range
9 9 -25. 6°F ~788°F 25. 6°F~1292°F 25. 6°F~1472°F 8 | SET button
9 | HI/LO button
LCD size 30mm*30mm 35mm*35mm 35mm*35mm 10] Laser switch button
11 Laser warning label
LCD display Color EBTN
<0°C: + (1.5°C+0.1°C/°C);20°C: +1.5°C or +1.5% of reading, whichever is greater a Lock measurement indicator
Accuracy <32°F: + (3.0°F+0.1°F/°F); >32°F: +3.0°F or +1.5% of reading, whichever is greater ag Buzzer indicator en
. +0.1°C/°C or +0.1%/°C, whichever is greater rs
Temperature coefficient (40.1°F/°F or £0.1%/”F, whichever is greater) HI OK LO| Temperature measurement alarm indicator a HI og oO K LO aA
Repeatability 0.7°C or 0.7%, whichever is greater (1.5°F or 0.7%, whichever is greater) | Low battery indicator = 088 HOLD SCAN oe
Emissivity 0.1~1.0 (adjustable, can store 5 sets of preset values) SCAN | Temperature measurement indicator <,
Response time <250ms (95% of reading) HOLD | Temperature hold indicator ri iy ’
Spectral response 8um~14um “C°F | Temperature unit indicator x Ce iL Ht
Auto power off 15s 88a Main display of the measured temperature Fae
Low battery indication Vv 8888 | Auxiliary display of the measured temperature | wax AX MIN c rl, rm mn
High/Low temperature LED alam| vy = Emissivity indication
€-0.88 ave pir LNAI
High/Low temperature audible alarm) =v A Laser indicator 8 —
Data hold v max MIN Measurement mode indication
Unit conversion (°C/°F . .
corr) v Operating Instructions
MAX/MIN/AVG/DIF mode v Viewing the Last Measured Value
In the off state, short press (less than 0.5s) the trigger to turn on the thermometer and the measurement data held
Lock measurement v before last shutdown will be displayed. Toggle to view the MAX/MIN/AVG/DIF value by short pressing the MODE
button.
Auto Power Off
In the HOLD mode, if there is no operation for 15s, the thermometer will automatically power off and save the
currently held measurement.
Manual Measurement
1. Pull and hold the trigger after aiming at the target. The SCAN icon will be flashing indicating that the target
object temperature is being measured. The measurement result will be updated on the LCD.
2. Release the trigger, the SCAN icon disappears, and the HOLD icon appears, indicating that the measurement
has been stopped and the last measured value is held.
Lock Measurement
Description:
@ In the lock measurement function setting interface, the lock measurement time (1 minute to 5 hours) can be set.
Refer to Lock Measurement Seiting for details.
© After time setting, the measurement starts after the activation of the lock function. When the set time is reached,
the thermometer will automatically power off and save the last measured value.
e You can view the measured values by short pressing (less than 0.5s) the trigger (NOTE: The measured values
will be cleared by long press). This operation is applicable to processes that require regular monitoring of
temperature. If no timing is needed, just do not set the time.
Operation:
1. When the lock measurement function is turned on, short press the trigger to enable it. The @ icon will appear
on the thermometer screen and the SCAN icon will flash. The thermometer will continuously measure the target
temperature.
2. Pull the trigger again, the and SCAN icons disappear, and the HOLD icon appears. The thermometer stops
the measurement and holds the last measured value.
NOTE: During measurement, it is best to ensure that the measured target diameter is twice the spot
slze (S) of the thermometer, and then determine the test distance (D) according to the D:S diagram (refer
to D:S part).
For example, If you use the UT301A+ to measure the temperature of an object with a dlameter of about 4”
(10cm), then according to the above, the spot size (S) of the thermometer should be about 2” (5cm) for
highest accuracy, and according to the D:S diagram, the measured distance (D) is about 24” (60 cm).
MAX/MIN/AVG/DIF Value Reading
Short press the MODE button to switch the “MAX—MIN-AVG—DIF’” measurement mode in tum and the temperature
value of the corresponding mode will be shown in the auxiliary display area (as shown below).
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Laser Indication Function On/Off
Short press the Ad button to turn on/off the laser indication function. When it is turned on, the laser indicator A,
will be displayed on the LCD, and the laser will accurately indicate the position you are measuring during temperature
measurement.
NOTE: Please follow the laser precautions when the laser is turned on to avoid damage to human or
animal eyes.
High/Low Temperature Alarm On/Off
Short press the HI/LO button to turn the high/low limit alarm function on and off in sequence.
When HI limit alarm function is turned on and the measured temperature value is higher than the set high alarm
limit, the red LED and HI indicator flash. If the audible alarm function has been turned on, the buzzer will beep.
When LO limit alarm function is turned on and the measured temperature value is lower than the set low alarm
limit, the blue LED and LO indicator flash. If the audible alarm function has been turned on, the buzzer will beep.
When HI/LO limit alarm function is tumed on and the measured temperature value is within the high and low alarm
limit range, the green LED lights up and the OK indicator is displayed, indicating that the measured temperature
is normal.
Function Setting
In the HOLD interface, short press the SET button to enter the settings of high alarm limit low alarm limit >
emissivity — temperature unit > audible alarm — lock measurement, etc. In these setting interfaces, pull the
trigger or do not operate for 10s to return to the HOLD interface.
High Alarm Limit Setting
In the HOLD interface, short press the SET button once to enter the high alarm limit setting interface.
Short press the Ax button to quickly select the preset high alarm limit value (P1-P5). If there is no desired value
among the preset values, select any value closest to the high alarm limit, and adjust it by pressing the ‘W button
or A button. Add or subtract 1 each time by short press, and add or subtract 10 per second by long press.
(see Figure 1)
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Figure 2
Figure 3
Figure 1
Low Alarm Limit Setting
In the HOLD interface, short press the SET button twice to enter the low alarm limit setting interface, and adjust
the low alarm limit value by pressing the W button or A button. Add or subtract 1 each time by short press, and
add or subtract 10 per second by long press. (see Figure 2)
Emissivity Setting
In the HOLD interface, short press the SET button until emissivity setting is displayed. Short press the Ad button
to quickly select the preset emissivity value (P1-P5). If no desired value among the preset values, select any value
closest to the emissivity, and adjust it by pressing the W button or A button. Add or subtract 0.01 each time by
short press, and add or subtract 0.1 per second by long press. (see Figure 3)
Temperature Unit Setting
In the HOLD interface, short press the SET button until temperature unit setting is displayed, and switch between
°C and °F by pressing the W button or A button.
Audible Alarm Setting
In the HOLD interface, short press the SET button until audible alarm setting is displayed, and turn on/off the audible
alarm by pressing the ‘W button or A button.
Lock Measurement Setting
In the HOLD interface, short press the SET button until lock measurement setting is displayed, and tum on/off the
lock measurement by pressing the W button or A button. When the lock measurement is turned on, press the Ay
button to perform the timing setting “00:00” for the lock measurement. At this time, the selected time position flashes,
and the time value can be adjusted by pressing the W button or A button. Set timing to “00:00” to turn off timing
function.
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D:S (Distance Coefficient)
As the distance (D) from the target being measured to the thermometer increases, the spot size (S) on the measured area
becomes larger. The relationship between the distance and the spot size is as shown below.
Spot Size @ Distance D:S=12:1
Spot Size @ Distance D-S=20:1
Spot Size @ Distance D:S=30:1
25@60
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UT301At+ D:S=12:1
UT302A+ D:S=20:1
UT303A+ D:S=30:1
Field of View
Make sure that the measured target is larger than the spot size. The smaller the target, the closer the test distance should
be (please refer to D:S for the spot size at different distances). To obtain the optimum measurement result, it is recommended
that the target being measured is 2 times larger than the spot size.
Emissivity
Emissivity is a symbol of the energy radiation of a material. The emissivity of most organic materials and coated or oxidized
surfaces is about 0.95. To measure the temperature of a bright metal surface, cover the surface to be tested with masking
tape or matt black paint with a high emissivity setting ((f it is possible), wait for a period of time, and measure the temperature
of the tape or black paint surface when it reaches the same temperature on the surface of the object covered below. The
total emissivity of some metals and non-metals are listed in the following table.
Target > spot size |
Target = spot size. .
Target < spot size
Measured Surfaces Emissivity
Metal
Aluminum
Oxidization 0.2-0.4
A3003 Alloy
Oxidization 0.3
Rough 0.1-0.3
Brass
Burnishing 0.3
Oxidization 0.5
Copper
Oxidization 0.4-0.8
Electric Terminal Board 0.6
Hastelloy
Alloy 0.3-0.8
Inconel
Oxidization 0.7-0.95
Sand-Blasting 0.3-0.6
Electro Burnishing 0.15
Iron
Oxidization 0.5-0.9
Rusting 0.5-0.7
Iron (Casting)
Oxidization 0.6-0.95
Non-Oxidization 0.2
Casting 0.2-0.3
Iron (Forging)
Passivation 0.9
Lead
Rough 0.4
Oxidization 0.2-0.6
Molybdenum
Oxidization 0.2-0.6
Nickel
Oxidization 0.2-0.5
Platinum
Black 0.9
0.7-0.9
Steel Plate Rubbing 0.4-0.6
Steel Plate Burnishing 041
Zinc
Oxidization 0.1
Non-Metal
Asbestos 0.95
Asphalt 0.95
Basalt 0.7
Carbon
Non-Oxidization 0.8-0.9
Graphite 0.7-0.8
Silicon Carbide 0.9
Ceramics 0.95
Clay 0.95
Concrete 9.95
Cloth 0.9
Glass
Convex Glass 0.76-0.8
Smooth Glass 0.92-0.94
Lead-Boron Glass 0.78-0.82
Plates 0.96
Plaster 0.8-0.95
Ice 0.98
Limestone 0.98
Paper 0.95
Plastics 0.95
Water 0.93
Soil 0.9-0.98
Wood 0.9-0.95
Maintenance
Clean
Use clean compressed air to blow away falling particles.
Use wet cotton swab to carefully wipe lens surface.
Use wet sponge or soft cloth to clean product exterior.
Do not rinse the thermometer or immerse it in water.
Battery Replacement
Install or replace a 9V battery (6F22) as follows:
1. Open the battery cover.
2. Insert the battery and pay attention to the polarity.
3. Close the battery cover.
Troubleshooting
Symptom
Problem
Action
OL appears when measuring
Measured value is greater
than the maximum range
Stop measuring
-OL appears when measuring
Measured value is less
than the minimum range
Stop measuring
Err appears when booting
Exceeding the minimum or
maximum operating ambient
temperature
Place the thermometer in a 0°C~50°C
(32°F~122°F) environment and it can be
recovered after 30 minutes
Battery indicator flashes
Low battery
Replace the battery
Laser fails to work /
weak laser
Low battery
Replace the battery
The measurement is
inaccurate
Emissivity mismatching, measured
distance is too far, measured target
diameter is less than 20mm, etc.
Please refer to the instructions for field of
view, D:S, etc.
UNI-T.
UNI-TREND TECHNOLOGY (CHINA) CO.,LTD.
No.6, Gong Ye Bei 1st Road,
Songshan Lake National
High-Tech Industrial
Development Zone, Dongguan City,
Guangdong Province, China
Tel: (86-769) 8572 3888
www.uni-trend.com
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UNI-T UT302+ UT303+ Series Infrared
Thermometers User Manual PDF Download
